What is a Conifer?

 Fir trees are one of the most common types of trees worldwide. They are known primarily for making spectacular Christmas trees, but they can be so much more varied than that. Fir trees make great trees because they are relatively easy to care for and can grow almost anywhere.

If you like the look of classic Christmas trees or think that your landscaping could use a boost from the addition of easy-to-manage evergreen trees, firs can make a great addition to any yard or property. There are a lot of different kinds of fir trees and this list will cover the most common species as well as all of the species that grow best in North America.

 Any of the five species of the genus Thuja, resinous, evergreen ornamental and timber conifers of the cypress family (Cupressaceae), native to North America and eastern Asia. A closely related genus is false arborvitae.

Arborvitae are trees or shrubs, usually pyramidal in habit, with thin, scaling outer bark and fibrous inner bark, horizontal or ascending branches, and characteristically flattened, spraylike branchlet systems. Each branchlet has four rows of tiny, scalelike leaves. Juvenile leaves are much longer and needlelike and in some species may persist along with the mature foliage.

Male & female reproductive structures (cones) are borne at the tips of different branchlets of the same tree, the male cones rounded and reddish or yellowish, the female very small and green or tinged with purple. Mature cones are solitary, egg shaped or oblong, 8 to 16 millimetres (about 1/2 inch) long, with 4 to 6 (but sometimes 3 or as many as 10) pairs of thin, flexible scales that terminate in thickened ridges or processes. 

 Yellowish or reddish-brown arborvitae wood is soft, light in weight but very durable, fragrant, and easily worked. The giant arborvitae (T. plicata) is the most important timber-producing species, but the wood of the American arborvitae (T. occidentalis) is also frequently used. 

 Surprisingly, there are only four different types of true cedar trees. These trees have some pretty distinct differences, which is why they are considered completely different species. In fact, there are no native cedar trees in North America. Instead, these trees are all native to areas on the other side of the ocean.

However, there are quite a few “false” cedars. While these aren’t technically seen as “true” cedar trees, we commonly identify them as cedar trees in North America. These trees are similar to cedars, though they are not technically related at all.

 Cypress is another type of conifer. They are smaller than other trees, only growing to about 5-40 m tall. The leaves grow in opposite pairs and stay on for about three to five years. After that, they fall off. The leaves are about 5-15 mm long.

The cones take a bit to mature. Some don’t mature from pollination for two years. The seeds are quite small, and there are two narrow wings on each side.

There are many different types of cypress trees. Most are adapted in some way to forest fires. In some cases, the cones only open during wildfires after the mother tree has been destroyed. Then, the cone is released onto the bare ground, where they have little competition.

However, some species do simply release the seeds when they mature.

Many people mistakenly believe that all conifers are pine trees, though this is not the case. There are between 220 to 250 different species, depending on who you ask. Some people lump certain trees together as the same species, while other people separate them out into core species. 

 In North America alone, there are 49 species of native Pine trees. Not only are there tons of Pines around, but they are one of the most easily recognized trees. Even though many people can recognize a Pine, few know how to distinguish between the different species of Pines. 

 This family is often dominant in montane, boreal, and coastal forests. 

 There are only a few species in the Spruce family – 35 to be in fact. For this reason, they are one of the smaller conifer types. They are found in northern regions, particularly in temperate and boreal areas.  

They are decently large trees that can reach between 60 to 200 feet tall. Their needles are four-sided, and their cones hang downwards after they are pollinated. These characteristics set them apart from other types of conifers.

Spruce trees shed their leaves when they are 4-10 years old. During this period, their branches will be rough with retained pegs. In some cases, these trees do have smooth branches, though.

These trees play an important role in the lifecycle of some insect species. For instance, they are eaten by some moth and butterfly species. 

 Most spruces can easily be identified by their compact, narrow crown and drooping branchlets. These species grow in a variety of climates including coastal areas, high altitudes, and boreal forests.

Many types of spruce trees serve as ornamental plantings in urban parks and gardens, while others provide wood for construction beams, fences, or furniture making.

 Douglas-fir is a large conifer, evergreen tree in the Pinaceae (pine) family that grows 40 to 80 feet tall when cultivated but as tall as 300 feet in the wild. It is one of the largest trees in the world, and one of the most important timber species in the United States. Young trees have a narrow and spired pyramidal shape with lower branches drooping and upper branches ascending. As the tree matures, it becomes cylindrical, loses its lower branches and resulting in branching only at the top third of the tree. This tree has unique forked cone bracts that is distinctly different from many other conifers. The cones are about 3 to 4 inches long and pendulous. The needles are flat, spirally arranged, dark green and up to 1.25 inches long with white banding on the undersides. They are fragrant when bruised or crushed.  

 It is native to Southwestern British Columbia to West Central California. The Douglas-fir is the State tree of Oregon. It grows best in northern or northwestern climates of the United States.  

 Plant it in full sun, acidic to neutral, moist, well-drained, organically rich soil.  Keep it well watered since it is intolerant to drought. It is easy to transplant when it is small. The Douglas-fir is intolerant to heat, humidity, and warm temperatures at night. 

There are two distinctly different geographic varieties of the Douglas-fir. Coast Douglas-fir or var. menziesii is a large tree with dark yellow-green needles, large cones that is found on the Pacific coast.. The Rocky Mountain Douglas-fir or var. glauca is a medium-sized tree with shorter bluish-green needles, and small cones. Dwarf cultivars are available commercially. 

 These trees can live for thousands of years. However, there are quite a few threats to this species, such as logging, fires, and climate change. 

Larch trees are one of the few deciduous conifers, which means that they shed their pine needles regularly. Just like broad-leaf trees, these conifers will lose their needles every autumn. They are the dominant tree in the boreal forests of Canada and Siberia.

These trees usually reach around 65 to 120 feet tall. 

 The most widely distributed North American larch is called tamarack, hackmatack, or eastern larch (L. laricina). The bracts on its small cones are hidden by the scales. Eastern larch trees mature in 100 to 200 years. This species may grow about 40 to 65 feet tall and have gray to reddish brown bark. A taller species, the western larch (L. occidentalis) of the Pacific Northwest, has bracts that protrude beyond the cone scales. 

 The junipers include roughly 60 different species of trees and shrubs in the Juniperus genus, within the cypress family of plants. Although some junipers use the word "cedar" in their common names, juniper and cedar are not the same. Junipers are not members of the Cedrus genus. The leaves of these evergreen conifers usually take the form of flattened scales in the mature plants, though they may be needle-like in juvenile plants.

Most junipers offer at least some level of drought resistance, making them a good choice in more arid climates. But precautions should be taken in areas prone to wildfires. Junipers grow best in sunny spots with good soil drainage. Many people pick common juniper (Juniperus communis) as one of the best junipers for landscaping, but other varieties can be just as beautiful.

Many species are dioecious, meaning plants produce male or female parts but not both. It is generally the female plants that produce colorful berries, which are actually modified cones. The berry/cones of common juniper are used to flavor gin. Juniper fruits can also be used as a spice in cooking, and they are very attractive to many birds and other wildlife.

 The common name hemlock is derived from a perceived similarity in the smell of its crushed foliage to that of the unrelated plant poison hemlock. Unlike the latter, Tsuga species are not poisonous.  There are eight, nine, or ten species within the genus (depending on the authority), with four species occurring in North America and four to six in eastern Asia. 

Hemlocks are medium-sized to large evergreen trees, ranging from 35 to 200 feet (10 – 60 m) tall, with a conical to irregular crown, the latter occurring especially in some of the Asian species. The leading shoots generally droop. The bark is scaly and commonly deeply furrowed, with the color ranging from grey to brown. The branches stem horizontally from the trunk and are usually arranged in flattened sprays that bend downward towards their tips. Short spur shoots, which are present in many gymnosperms, are weakly to moderately developed. The young twigs as well as the distal portions of stem are flexible and often pendent. The stems are rough due to pulvini that persist after the leaves fall. Hemlock trees are more tolerant of heavy shade than other conifers; hemlocks are, however, more susceptible to drought. 

 The two eastern North American species, T. canadensis and T. caroliniana are under serious threat by the sap-sucking insect hemlock woolly adelgid or HWA (Adelges tsugae). This adelgid, related to the aphids, was introduced accidentally from eastern Asia, where it is only a minor pest. Extensive mortality has occurred, particularly east of the Appalachian Mountains. The Asian species are resistant to this pest, and the two western American hemlocks are moderately resistant. Tsuga species are also used as food plants by the larvae of some Lepidoptera species including the Autumnal Moth and the Engrailed, and older caterpillars of the Gypsy Moth. Once these infest a tree, they can do more than simply kill one tree. Larger hemlocks that are infected have large relatively high root systems that can bring other trees down if one falls. The foliage of young trees is often browsed by deer, and the seeds are eaten by finches and small rodents. 

 There isn’t actually a type of tree called the Yew. Instead, this term is used to refer to many different species that just happen to have the term “yew.” Many of these trees belong to the Taxus genus, which is also known as the yew family. However, there are some species that are referred to as “yew” that don’t actually belong to this family.

These trees are relatively long-lived and relatively slow-growing. They can reach up to 65 feet, though this is quite short compared to other trees on this list. This species is also very old, with fossils found from the Early Cretaceous.

These trees are often known as being poisonous. However, toxin changes between species. Some seeds are dangerously poisonous. Birds can often eat them fine because they cannot break down the outside of the seed. However, humans can, which releases the toxins inside the seed.

 It can withstand heavy pruning and utilized as a foundation plant, hedges, topiaries, screens, and undergrowth shrubs.  In hardiness zones 4 and lower, the foliage can burn or turn brown in the winter months.  When planted in warmer climates above zone 8 the plant can melt out in the winter.  

 Regular annual pruning will help keep the desired shape as well as allow the plant to achieve a dense carpet of needles.  The optimum planting location includes part sun and part shade.  Too much shade will decrease the growth rate, while too much sun can result in the plant drying out.  This is especially crucial with young plants. 

 Sequoia, genus of conifers of the bald cypress family (Taxodiaceae), comprising one species, Sequoia sempervirens (redwood). The big tree, or giant sequoia (Sequoiadendron giganteum), historically was included in this genus. The redwood is native in the fog belt of the Coast Ranges from southern Monterey county, Calif., to southern Oregon, U.S., and the big tree occurs in scattered groves on the westerly slopes of the Sierra Nevada from Placer to Tulare counties in California.

They are best located in cool, moist climates with consistent moisture.  They will grow in sandy loam-type soil with a consistent temperature range.  It will not tolerate drastic climate changes or clay soil. 

The bark is reddish-brown, spongy, ridged, furrowed, and textured (cork-like).

Forest fires are a high risk for seedlings and saplings.  As the tree ages, its rapid growth, fire-resistant bark, elevated canopies, and self-pruned lower branches place mature trees at a much lower risk of being killed by fire.  

The giant redwood requires a large space and the correct climate.